In recent years, the use of light-emitting diodes (LEDs) in development of light fixtures for various common lighting purposes has increased, and this trend has accelerated as advances have been made in the field. Indeed, lighting applications which previously had typically been served by fixtures using what are known as high-intensity discharge (HID) lamps are now being served by LED light fixtures. Such lighting applications include, among a good many others, roadway lighting, factory lighting, parking lot lighting, and commercial building lighting.
High-luminance light fixtures using LED modules as a light source present particularly challenging problems. One particularly challenging problem for high-luminance LED light fixtures relates to heat dissipation. Some of the advances in the field are disclosed in U.S. Pat. Nos. 7,686,469 and 8,070,306.
Improvement in dissipating heat to the atmosphere is one significant objective in the field of LED light fixtures. It is of importance for various reasons, one of which relates to extending the useful life of the lighting products. Achieving improvements without expensive additional structure and apparatus is much desired. This is because a major consideration in the development of high-luminance LED light fixtures for various high-volume applications, such as roadway lighting, is controlling product cost even while delivering improved light-fixture performance.
Another challenge is that LEDs produce high temperatures during operation and, in certain fixture orientations, need to be isolated from possible contact with flammable objects to avoid damage to LED optics, as well as to maintain intended light distribution characteristics.